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A261650
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Expansion of Product_{k>=0} ((1+x^(4*k+1))/(1-x^(4*k+1)))^2.
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2
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1, 4, 8, 12, 16, 24, 40, 60, 80, 104, 144, 204, 272, 344, 440, 584, 768, 968, 1200, 1516, 1936, 2424, 2968, 3644, 4528, 5596, 6800, 8216, 10000, 12184, 14688, 17564, 21056, 25320, 30272, 35912, 42576, 50616, 60024, 70728, 83136, 97896, 115200, 134924, 157504
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n) ~ exp(Pi*sqrt(n/2)) * 2^(3/2) * Gamma(1/4)^2 / (16 * Pi^(3/2) * sqrt(n)).
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MATHEMATICA
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nmax=60; CoefficientList[Series[Product[((1+x^(4*k+1))/(1-x^(4*k+1)))^2, {k, 0, nmax}], {x, 0, nmax}], x]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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